Rab25 influences functional Cav1.2 channel surface expression in arterial smooth muscle cells.

نویسندگان

  • John P Bannister
  • Simon Bulley
  • M Dennis Leo
  • Michael W Kidd
  • Jonathan H Jaggar
چکیده

Plasma membrane-localized CaV1.2 channels are the primary calcium (Ca(2+)) influx pathway in arterial smooth muscle cells (myocytes). CaV1.2 channels regulate several cellular functions, including contractility and gene expression, but the trafficking pathways that control the surface expression of these proteins are unclear. Similarly, expression and physiological functions of small Rab GTPases, proteins that control vesicular trafficking in arterial myocytes, are poorly understood. Here, we investigated Rab proteins that control functional surface abundance of CaV1.2 channels in cerebral artery myocytes. Western blotting indicated that Rab25, a GTPase previously associated with apical recycling endosomes, is expressed in cerebral artery myocytes. Immunofluorescence Förster resonance energy transfer (immunoFRET) microscopy demonstrated that Rab25 locates in close spatial proximity to CaV1.2 channels in myocytes. Rab25 knockdown using siRNA reduced CaV1.2 surface and intracellular abundance in arteries, as determined using arterial biotinylation. In contrast, CaV1.2 was not located nearby Rab11A or Rab4 and CaV1.2 protein was unaltered by Rab11A or Rab4A knockdown. Rab25 knockdown resulted in CaV1.2 degradation by a mechanism involving both lysosomal and proteasomal pathways and reduced whole cell CaV1.2 current density but did not alter voltage dependence of current activation or inactivation in isolated myocytes. Rab25 knockdown also inhibited depolarization (20-60 mM K(+)) and pressure-induced vasoconstriction (myogenic tone) in cerebral arteries. These data indicate that Rab25 is expressed in arterial myocytes where it promotes surface expression of CaV1.2 channels to control pressure- and depolarization-induced vasoconstriction.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Transcriptional upregulation of α2δ-1 elevates arterial smooth muscle cell voltage-dependent Ca2+ channel surface expression and cerebrovascular constriction in genetic hypertension.

A hallmark of hypertension is an increase in arterial myocyte voltage-dependent Ca2+ (CaV1.2) currents that induces pathological vasoconstriction. CaV1.2 channels are heteromeric complexes composed of a pore-forming CaV1.2α1 with auxiliary α2δ and β subunits. Molecular mechanisms that elevate CaV1.2 currents during hypertension and the potential contribution of CaV1.2 auxiliary subunits are unc...

متن کامل

Natural inequalities: why some L-type Ca2+ channels work harder than others

Introduction Voltage-gated L-type Ca channels are expressed in the surface membrane of neurons and muscle cells (Catterall, 2000). There, they regulate multiple processes including excitability, contraction, gene expression, and memory storage. L-type Ca channels are heteromeric complexes comprising a pore-forming 1 subunit and accessory , 2, and  subunits. The specific set of poreforming ...

متن کامل

Increased Coupled Gating of L-Type Ca Channels During Hypertension and Timothy Syndrome

Rationale: L-Type (Cav1.2) Ca channels are critical regulators of muscle and neural function. Although Cav1.2 channel activity varies regionally, little is known about the mechanisms underlying this heterogeneity. Objective: To test the hypothesis that Cav1.2 channels can gate coordinately. Methods and Results: We used optical and electrophysiological approaches to record Cav1.2 channel activit...

متن کامل

Increased coupled gating of L-type Ca2+ channels during hypertension and Timothy syndrome.

RATIONALE L-Type (Cav1.2) Ca(2+) channels are critical regulators of muscle and neural function. Although Cav1.2 channel activity varies regionally, little is known about the mechanisms underlying this heterogeneity. OBJECTIVE To test the hypothesis that Cav1.2 channels can gate coordinately. METHODS AND RESULTS We used optical and electrophysiological approaches to record Cav1.2 channel ac...

متن کامل

Truncation of murine CaV1.2 at Asp-1904 results in heart failure after birth.

The carboxyl-terminal intracellular tail of the L-type Ca(2+) channel CaV1.2 modulates various aspects of channel activity.For example, deletion of the carboxyl-terminal sequence at Ser-1905 increased CaV1.2 currents in an expression model. To verify this finding in an animal model, we inserted three stop codons at the corresponding Asp-1904 in the murine CaV1.2 gene. Mice homozygous for the St...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • American journal of physiology. Cell physiology

دوره 310 11  شماره 

صفحات  -

تاریخ انتشار 2016